Controller for alternating-current apparatus.



PATENTED AUG. 15, 1905.

R. 1 JACKSON. CONTROLLER FOR ALTERNATING CURRENT APPARATUS.

APPLICATION FILED JAIL 33, 1905.

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?17 INV NTOR WITNESSES: JAM. i4 w W o. ASA/AW;

ATTbRNEY PATENTBD AUG. 15, 1905.

R. P. JACKSON.

CONTROLLER FOR ALTERNATING CURRENT APPARATUS.

APPLICATION FILED JAN. 23, 1905.

2 SHEETS-SHEET 2.

2 p lNVENTOR ATTO'RNEY WITNESSES:

plied to them, and this is commonly done by UNITED STATES PATENT OFFICE.

RAY P. JACKSON, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC & MANUFACTURING COMPANY, A COR- PORATION OF PENNSYLVANIA.

CONTROLLER FOR ALTERNATlNG-CURRENT APPARATUS- Application filed January23,

To all whom, it may concern.-

Be it known that I, RAY P. J AOKSON, a citizen of the United States, anda resident of VVilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in Controllersfor Alternating-Current Apparatus, of which the following is aspecification.

My invention relates to controllers for electrical apparatus, andparticularly to controllers for supplying large currents at variablevoltages to translating devices that are operated by means ofalternating-current energy.

My invention has for its object to provide means for preventinginjurious arcing between the circuit making and breaking contactsurfaces of controllers which are employed for the above-stated purpose.

The speeds of alternating-current motors may be varied by varying thevoltages apvarying the active lengths of the windings of thetransformers from which the motors are supplied with energy. In theoperation of controllers which are employed for varying the activelengths of such transformer-windings the motor-circuits are broken ateach variation step in the voltage or portions of the maintransformer-windings are temporarily short-circuited, and dangerous anddestructive arcs are usually produced when either of these changes takesplace.

My invention provides simple means for reducing arcing to such an extentthat it does not seriously affect the operation of controllers, and suchmeans are illustrated in the accompanying drawings, in which Figure l isa diagrammatic view of a simple system embodying the invention. Fig. 2represents in development a controller employed in practicing myinvention. Figs. 3 and 4 are views corresponding to Fig. 2, butillustrating modifications.

Alternating-current energy is supplied from a suitable source 1 to amain transformerwinding 2, which is subdivided by means of spaced leads3 4 5 6, &c., one terminal of a motor 7 being connected to terminal 8 ofsaid winding or to any other suitable point in that winding. The speedof the motor 7 may be varied by varying the voltage applied to itsterminals, which in this case may be done by connecting terminal 9 ofthe motor directly Specification of Letters Patent.

Patented Aug. 15, 1905.

1905. Serial No. 242,314.

and successively to the respective leads 3 4 5 6. &c.

In case the motor 7 is of large capacity, however, the arcs produced bysevering a direct connection between the terminal 9 and the severalleads 3 4 5 6, 620., may be of such character and proportions as tocause serious damage to the contact-surfaces and possible injury to theoperator. To avoid this objection, I provide a regulating device 13,having comparatively high ohmic resistance, and an inductive regulatingdevice 14, having very little ohmic resistance, and connect them inparallel between two contact-terminals 10 and 11, which are adapted toengage, respectively, with adjacent contact-terminals 12 12 12 12, &c.,of the respective leads 3 4 5 6, &c. The middle points or any other twosuitable intermediate points of the resistances 13 and 14 are connectedtogether and to the terminal 9 of the motor 7.

If the contact-terminals 10 and 11 engage, respectively, with thecorresponding contactterminals 12 and 12 current is supplied to themotor 7 from the leads 4 and 5 through the portions 16 and 17 of thedevice 14 to the terminal 9 of the motor 7. Lead 5 being of higherpotential than lead 4, the voltage impressed upon the portion 16 will begreater than that impressed upon the portion 17 of the winding 14; butthese two portions are in the same magnetic circuit, and hence there isa tendency to equalize the potential differences between the middlepoint 19 of the device 14 and the terminals 10 and 11 because of theinductive action of portion 16 upon portion 17. The voltage impressedupon the terminals of the motor 7 is approximately equal to thedifference of potential between the terminal 8 and a point in thewinding 2 midway between the point of attachment thereto of the leads 4and 5. There is a slight difference in the values of the currents in thetwo portions 16 and 17 of the device 14, because the portion 16 mustsupply the current required to magnetize the iron in the magneticcircuit.

It is evident that the portion of the main transformer-winding 2included between the leads 4 and 5 is short-circuited when thecontroller is in the position just described; but the ohmic resistancedevice 13 is included in that circuit and the current is thereby reducedto a comparatively small value.

If it is desired to supply a higher voltage to the motor 7, thecontact-terminal 10 should be moved to make contact with thecontactterminal 12. In severing connection between the contact-terminal10 and the terminal 12 a slight sparking or arcing may occur, due to theinterrupting of the local circuit; but this arcing is much less thanordinarily occurs in such apparatus, owing to the fact that thedifferences of potential between the contact-terminals 10 and 11 and themiddle point 19 ot' the regulating device 14 are approximately equal andbecause the portions 15 and 16 of the respective devices 13 and 14 areamply able to conduct the current required by the motor 7.

After the contact-terminal 10 is disconnected from the terminal 12current is supplied to the motor 7 through the portions 15 and 16 of theregulating devices 13 and 14 in paral lel, and it has been found thatthe best results are obtained when the devices are so proportioned thatthe currents in these two portlons are approximately equal. Since theportions 16 and 17 of the device 14 are in the same magnetic circuit, avoltage is induced in the portion 17 approximately equal to thatimpressed upon the portion 16, a closed circuit being formed by theportions 17 and 18 of the devices 14 and 13. Since these circuits orsimilar ones are always complete, compara tively little sparking willoccur when changing the connections of the terminals 10 and 11 with themain transformer-winding whether passing from a lower to a higher orfrom a higher to a lower voltage connection.

Instead of moving the contact 10 from ter- 'minal 12 to terminal 12 thecontacttermi- .nal 11 might be moved to make contact with the terminal12 and the contact-terminal be moved to make contact with the terminal:12; but if this should be done it would be necessary to break thecontact between the contact-terminal l0 and the terminal 12 and bringterminal 10 into engagement with the terminal 12 before breaking thecorresponding contact between terminal 11 and the terminal 12 in orderto secure the advantages 'of my invention.

In Fig. 2 I have shown in development a suitable controller forpracticing my invention, the elements and connections of which are soarranged that the direction of the drop of potential through theregulating devices 13 and 14 is alternately reversed.

ance devices 13 and 14 and a branch circuit being provided from theterminal 8 through finger 27, contact-segments 23, 24, and 24, fingers28 and 28, and portions 17 and 18 of resistance devices 14 and 13.

In the position b of the controller-drum 20 contact is broken betweenthe drum-segment 23 and the contactfinger 27 and drum-segment 29 andcontact-finger 30 engage each other, a main circuit for the motor beingthus provided from-its terminal 8 through the portion of the maintransformer-winding 2 included between the terminal 8 and lead 4,contact-finger 30, drum-segments 29 24, and 24, contact-fingers 28 and28, and portions 18 and 17,respectively,of the ohmicand inductiveresistance devices 13 and 14 and a branch circuit being provided fromthe terminal 8 through that portion of the transformer-winding 2 betweenit and the lead 3, finger 26, segments 22, 21, and 21, fingers 25 and25, and portions and 16 of the resistance devices 13 and 14.

For the remainder of the positions of the controller-drum the operationis similar to that just described.

It is evident from the above description that the main circuit of themotor is alternately through the portions 18 and 17 and the portions 15and 16, respectively, of the ohmic and inductive resistance devices 13and 14.

hen the controller-drum has reached its last position 9, or thatcorresponding to full-speed running of the motor 7, the contact-fingersand 28 become disengaged from the corresponding drum-segments 21 and 24,whereby the non-inductive resistance device 13 is cut out of circuit andthe losses in the controller are reduced toa minimum.

The combination and arrangement of the regulating devices with the otherparts of the controller which I have thus far described are those whichhave been found most effectual in preventing sparking when changing thecircuit connections and in minimizing the energy losses in thecontroller when it occupies normal running positions. Sparking isprevented because the circuits of the motor and of the inductiveregulating device are never interrupted, but are only altered whenchanges in the positions of the controller take place, and owing to thecomparatively high ohmic resistance of the non-inductive regulatingdevice 13 very little energy loss occurs therein, the greater portion ofthe current that is supplied to the motor 7 traversing the inductiveregulating device 14, the ohmic resistance of which should be low. Itmay be found, however, in many cases that if only a single regulatingdevice is employed of one character or the other in place of two thatdifier in character certain advantageous results may be secured.

In Fig. 3.1 have shown a controller cmbodying only an inductiveregulating device 31. With this modification a limited amount ofsparking will occur when changing the circuit connections, owing to theinterruptions of the circuit of the inductive regulating device 81,though the energy losses in the said iievices may be very small if itsresistance is ovv.

In the modification of Fig. 4 only a noninductive regulating device 32is employed, and as a result the energy .losses in the ohmic resistancemay be rather large, though not necessarily excessive, While thesparking at the controller contact-terminals may be almost negligible.

While I have shown and described my in vention as utilized incontrolling a single motor, it is evident that it may be employed tocontrol a plurality of motors which are connected either in series or inparallel relation to each other and that it may be employed to controlany type of alternating-current motor or any other suitable translatingdevice or devices. It will be understood, therefore, that the claims areto be so construed as to cover either a single translating device or aplurality of such devices, according to the service conditions that mayprevail, and that the kind or type of such devices may be such as thegiven conditions of service may require.

I claim as my invention 1. The combination with a source ofalternating-current energy and a transformerwinding connected thereto,of a suitable translating device having a terminal connected to saidwinding, an ohmic resistance and an inductive resistance connected inparallel with each other and having their middle points connectedtogether and to the other terminal of said translating device ordevices, and means for connecting the terminals of the said ohmic andinductive resistances to diiferent points in the transformer-winding.

2. The combination with a source of alternating current energy and atransformerwinding connected thereto, of a suitable translating devicehaving a terminal connected to said winding, an ohmic resistance and aninductive resistance connected in parallel with each other and havingtheir middle points connected together and to the other terminal of saidtranslating device or devices, and means for connecting the terminals ofthe said ohmic and inductive resistances to diflerent points in thetransformer-Winding and for reversing the direction of the drop ofpotential over said ohmic and inductive resistances with each change inthe voltage.

3. The combination with a source of alternating current energy and atransformer- Winding connected thereto, of a suitable translating devicehaving a terminal connected to said winding, an ohmic resistance and aninductive resistance connected in parallel with each other and havingpoints intermediate their terminals connected together and to the otherterminal of said translating device, and means for connecting theterminals of the said ohmic and inductive resistances to differentpoints in the transformer-Winding.

I. The combination with a source of electrical energy of differentvoltages and a translating device supplied therefrom, of an ohmicresistance and an inductive resistance con nected in parallel with eachother and having their middle points connected together and to aterminal of said translating device, and means for connecting theterminals of the ohmic and inductive resistances to points which aresupplied from said source and which differ in potential.

5. The combinationwith a source of electrical energy of difierentvoltages and a translating device supplied therefrom, of an ohmicresistance and an inductive resistance connected in parallel with eachother and having their middle points connected together and to aterminal of said translating device, and means for connecting theterminals of the ohmic and inductive resistances to points which aresupplied from said source and which differ in potential and forreversing the direction of the drop of potential over the said ohmic andinductive resistances with each variation in the voltage.

6. The combination with a source of electrical energy of diiferentvoltages and a translating device supplied therefrom, of an ohmicresistance and an inductive resistance connected in parallel with eachother and having points intermediate their terminals connected togetherand to a terminal of said translating device. and means for connectingthe terminals of the ohmic and inductive resistances to points which aresupplied from said source and which differ in potential.

7. The combination with a source of alternating-current energy and atransformerwinding connected thereto, of a suitable translating devicehaving a terminal connected to said Winding, two regulating-windingsconnected in parallel with each other and having their middle pointsconnected together and to the other terminal of said translating deviceor devices, and means for connecting the terminals of theregulating-windings to different points in the transformer-winding.

8. The combination with a source of alternating-current energy and atransformerwinding connected thereto, of a suitable translating devicehaving a terminal connected to said winding, two regulating-windingsconnected in parallel with each other and having their middle pointsconnected together and to the other terminal of said translating deviceor devices, and means for connecting the terminals of the saidregulating-windings to different points in the transformer-winding andfor reversing the direction of the drop of potential over saidregulating-windings with each change .in the voltage.

9. The combination with a source of alternating-current energy and atransformerwinding connected thereto, of a suitable translating devicehaving a terminal connected to said winding, two regulating-windingsconnected in parallel with each other and having points intermediatetheir terminals connected together and to the other terminal of saidtranslating device, and means for connecting the terminals of the saidregulating-windings to different points in the transformer-winchng.

10. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of two regulatingwindingsconnected in parallel with each other and having their middle pointsconnected together and to a terminal of said translating device, andmeans for connecting the terminals of the regulatingwindings to pointswhich are supplied from said source and which differ in potential.

11. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of two regulatingwindingsconnected in parallel with each other and having their middle pointsconnected together and to a terminal of said translating device, andmeans for connecting the terminals of the regulatingwindings to pointswhich are supplied from said source and which differ in potential andfor reversing the direction of the drop of potential over the saidregulating-windings with each variation in voltage.

12. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of two regulating windingsconnected in parallel with each other and having points intermediatetheir terminals connected together and to a terminal of said translatingdevice, and means for conneeting the terminals of theregulating-windings to points which are supplied from said source andwhich differ in potential.

13. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulatingwindinghaving its middle point connected to one terminal of said translatingdevice and means for connecting the terminals of the regulating-windingto points which are supplied from said source and which differ inpotential.

14. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulatingwindinghaving its middle point connected to one terminal of said translatingdevice and means for connecting the terminals of the regulating-windingto points which are supplied from said source and which differ inpotential and for reversing the direction of the drop of potential overthe said regulatingwinding with each variation in voltage.

15. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulatingwindinghaving a point intermediate its terminals connected to one terminal ofsaid translating device, and means for connecting the terminals of theregulating-winding to points which are supplied from said source andwhich differ in potential.

16. The combination with a source of alternating-current energy and atransformerwinding connected thereto, of a suitable translating devicehaving a terminal connected to said winding, two regulating resistancedevices connected in parallel with each other and having pointsintermediate their terminals connected together and to the otherterminal of said translating device, and means for connecting theterminals of the said regulating resistance devices to different pointsin the transformer-winding.

17. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of two regulating devicesconnected in parallel with each other and having their middle pointsconnected together and to a terminal of said translating device, andmeans for connecting the terminals of the regulating devices to pointswhich are supplied from said source and which differ in potential.

18. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulating resistancehaving its middle point connected to one terminal of said translatingdevice and means for connecting the terminals of the regulatingresistance to points which are supplied from said source and whichdiffer in potential.

19. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulating resistancehaving its middle point connected to one terminal of said translatingdevice and means for connecting the terminals of the regulatingresistance to points which are supplied from said source and whichdiffer in potential and for reversing the direction of the drop ofpotential over the said regulating resistance with each variation involtage.

20. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulating resistancehaving a point intermediate its terminals connected to one terminal ofsaid translating device, and means for connecting the terminals of theregulating resistance to points which are supplied from said source andwhich differ in potential.

21. The combination with a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulatingwindinghaving its middle point connected to one terminal of said translatingdevice and means for connecting each terminal of the regto one terminalof said translating device and means for connecting each terminal of theregulating resistance to difierent-voltage terminals that lead fromsaidsource.

24. The combination With a source of variable-voltage electrical energyand a translating device supplied therefrom, of a regulating resistancehaving a point intermediate its terminals connected to one terminal ofsaid translating device, and means for connecting each terminal of theregulating resistance to dif ferent-voltage terminals that lead fromsaid source.

25. The combination With a source of variable-voltage electrical energyand an electric motor supplied therefrom, of a regulating resistance,approximately the middle point of Which is connected to one of themotor-terminals, and means for connecting each of theresistance-terminals to different-voltage terminals that lead from saidsource.

In testimony whereof I have hereunto subscribed my name this 20th day ofJanuary, 1905.

RAY P. JACKSON.

Witnesses:

F. E. VVYNNE, BIRNEY HINEs.

